In a sealed type scroll compressor, for example, as disclosed in U.S. Pat. No. 4,545,747, refrigerant gas compressed by a compression mechanism portion once passes the outer peripheral portion of a motor stator. After oil is separated from the gas at the lower portion of a chamber, the gas goes up through the outer peripheral portion of the motor stator again to an upper space of a motor chamber. Further the gas is introduced to the outside via a discharge pipe, and thus a gas flow passage is defined. Such a directional conversion function of the gas flow passage within the motor chamber has its limit in oil separating efficiency in a sealed container. Accordingly, the amount of oil flowing out from the discharge pipe of the compressor, so-called, the oil rising amount (oil discharge amount) is increased.
Particularly, in the case where the scroll compressor is operated by an inverter drive, the above-described oil rising phenomenon becomes conspicuous when the rotational speed of the compressor is increased. There is a fear that an increase of the oil rising amount of the compressor decreases the efficiency and reliability of an overall refrigerating cycle (for example, a decrease of heat exchanging efficiency of a heat exchanger, an increase of pressure loss of pipes and so on), to say nothing of the reliability of the compressor itself. Also, a reduction in size and weight of the compressor as a whole is an important problem in addition to the problem regarding the above-mentioned oil rising amount. The outer dimensions of the sealed container, especially its outer diameter is therefore decreased as much as possible for reducing its size and weight. Succeedingly, a gap between the outer peripheral portion of the motor stator and the inner wall surface of a body portion of the sealed container is obliged to be narrow. For example, the size of such a gap in an air-conditioning scroll compressor of 2.2 kw-3.75 kw is approximately 2 mm. If the gap size at the stator outer peripheral portion is small as above, oil becomes more easily stored at the stator upper portion from the viewpoint of oil separation, and thus stored oil is blown up by the refrigerant gas to result in promotion of the oil rising phenomenon. For this reason, it is important to enhance the function of the oil's flowing down in the narrow gap at the outer periphery of the motor stator in order to facilitate the oil separation within the sealed container.